Abstract

A previous computational study on dehydrated LTA zeolites [J. Gulín-González, G.B. Suffritti, Micropor. Mesopor. Mater. 69 (2004) 127] suggested the reversible amorphization of calcined LTA samples at pressures below 6 GPa, in agreement with the experimental results. However, the effect of guest molecules on the amorphization process was not evaluated in that study. In this paper, the potential reversible amorphization of Xe containing-LTA samples under high external pressures is studied via energy minimization calculations. The results of the simulations confirmed the pressure-induced amorphization of LTA zeolites at pressures about 2–4 GPa for all the studied samples. Besides, the simulations stressed the importance of the structural topology, particularly of D4R secondary units, for the recovering of the crystalline order. According to our calculations the exchangeable cations (Na⁺ and Li⁺) play a crucial role in the process of amorphization. Our results suggest that the reversible amorphization is essentially independent on the presence of Xe molecules in the range of the pressures studied (P ≤ 6 GPa).

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